Nested Plastic Tank Design for Shipping Volume Reduction
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Solution Overview
Problem
Current methods for manufacturing molded plastic water storage tanks are costly due to high shipping expenses and require complex assembly, and existing designs lack effective sealing and visibility into the water quality, especially for potable water storage.
Innovation Solution
A two-piece plastic water storage tank design with a nested configuration for compact shipping, featuring a composite wall with a thin interior liner made of higher-grade material for water contact and a secure joint system using elastic engagement, clips, serrations, and rotating tabs for easy assembly and sealing, while allowing for cost-effective production using injection molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a one-piece tank is manufactured by blow molding or rotational molding, then the tank structure is simple and strong, but the shipping cost becomes unacceptably high due to the large volume occupied by the complete tank
Solution Approach 1:
The tank is divided into two separate halves (upper and lower portions) that can be manufactured independently and shipped in a compact nested configuration. The portions are then assembled together with a mid-elevation joint to form the complete tank, reducing shipping volume while maintaining structural integrity through the joint connection.
Solution Approach 2:
The upper tank portion is designed to nest within the lower tank portion (or vice versa) during shipping and storage, significantly reducing the volume occupied by the tank components. This nesting capability allows compact packaging and transportation while the portions are assembled at the destination to form the complete functional tank.
2Loss of energy
If manufacturing sites are dispersed around the country to reduce shipping costs, then the shipping distance is reduced, but the product cost increases due to duplication of manufacturing facilities and high machinery or tooling costs for lower volume products
Solution Approach 1:
By segmenting the tank into two manufacturable portions that can be produced at a single centralized facility, the invention avoids the need to disperse manufacturing sites. The segmented design allows each portion to be manufactured efficiently using standard molding processes, and the portions are shipped in a nested configuration to minimize transportation costs, thereby avoiding both the high costs of dispersed facilities and the high shipping costs of complete tanks.
3Volume of moving object
If a tank is made from mating identical half tanks secured by clamps or welding, then the tank can be shipped compactly, but the joint assembly becomes complex and time-consuming
Solution Approach 1:
The tank is segmented into upper and lower portions with complementary joining features. The segmentation enables compact nested shipping while the portions are designed with integrated joining mechanisms that simplify assembly at the destination.
Solution Approach 2:
The joining function is merged into the tank portions themselves through integrated features such as interlocking rims, snap-fit mechanisms, or integrated sealing flanges. This eliminates the need for separate clamps or complex welding procedures, allowing the portions to be joined quickly and easily at the mid-elevation joint while maintaining a secure connection.
4Ease of manufacture
If a thin interior liner of higher grade material is used to provide water-contacting surface and visibility, then the material cost is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The tank employs a composite wall structure consisting of an outer substrate layer made of cost-effective plastic material and an inner liner layer made of higher-grade material suitable for potable water contact. The liner is integrally adhered to the substrate during the injection molding process, creating a bonded composite structure that combines the advantages of both materials while eliminating the need for separate manufacturing and assembly steps.
Solution Approach 2:
The manufacturing of the substrate and liner is merged into a single integral injection molding process. The liner is positioned within the mold cavity before substrate material is injected, and the substrate material bonds to the liner during curing, creating a permanently bonded composite structure in one manufacturing step.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design reduces manufacturing and shipping costs, provides a secure and easy-to-assemble tank with improved visibility into water clarity and purity, and ensures effective sealing against contamination and sunlight penetration.
Implementation Method 1
The tank wall will be opaque to inhibit passage of sunlight
Implementation Method 2
a joint comprised of elastically engageable circumscribing rims
Data Source
AI summary
A method of making a plastic tank suitable for containing water comprises forming a tank base which is partially or fully lined with a plastic layer that is different in character or color from the plastic material of the substrate of the tank base. The tank is alternatively formed by injection molding substrate material around the core of a mold which is partially or fully covered by the liner material, and by injecting liner material into the mold to bond it to the tank base substrate in conjunction with retracting part or all of the core, to provide space in the mold for the liner material.